This invention relates to the field of devices for minimizing and absorbing the shock forces transmitted to a railway car and its cargo resulting from the railway trucks under the car pivoting slightly back and forth between the opposite rails of the railway track as the train moves down the track.
Prior art devices of this kind of which the inventor is aware include those described in the following United States patents:
Pat. No. 3,865,045 discloses a device for damping objectionable oscillations of railway trucks about their swivel axes, comprising a pair of reciprocating plungers on opposite sides of the railway car and truck assembly, biased outwardly, having one end connected to a bracket secured to respective sides of the railway car and the other end connected to respective sides of the truck assembly. When the truck assembly starts to pivot in one direction the outwardly biased plunger on that side resists pivotal movement in that direction, and the same for the plunger on the other side when the truck assembly starts to pivot in that direction.
Pat. No. 3,420,548 discloses a hydraulic control device for semi-trailer and truck combinations, and the like, to resist the tendency to jackknife. It includes a cylindrical hydraulic chamber having a rotatable vane mounted at a location substantially parallel to the axis of rotation of the trailer and tractor. The rotatable vane is connected through a lever to the trailer and applies resistance to rotation of the trailer relative to the tractor thus resisting the tendency to jackknife.
Pat. No. 3,162,275 discloses a tension compression link assembly having a reciprocating rod received in an elongated cylinder or casing in which friction brake type elements are supported to apply compressive friction resistance to reciprocating movement of the rod, one end of the cylinder and rod assembly being connected to an outer end of the railway truck bolster, the other end being connected to the railway car frame.
Pat. No. 3,020,857 discloses a friction type shock absorber comprising a cylinder and plunger having a friction type brake shoe to frictionally resist reciprocating movement within the cylinder or barrel, the cylinder assembly including a barrier or stop to limit reciprocating movement of the plunger into the barrel, one of the shock absorbers connected to an outer edge of the railway car body, the other end connected to an outer end of the truck bolster.
Pat. No. 2,705,926 discloses a first rotary vane hydraulic type shock absorber secured to one corner of a railway truck assembly and a second one secured to the diagonally opposed corner thereof, the operating levers of the rotary shock absorbers being pivotally connected to link members which are secured to adjacent portions of the railway car body, to resist forces applied in a substantially horizontal plane between the railway truck and car body such as the horizontal lateral sinusoidal oscillation of the truck assembly which the inventor in that case calls "nosing."
Pat. No. 2,464,760 discloses a railway truck stabilizing mechanism comprising an articulated link assembly connected at its upper end to the center sill 13 of the railway car body and at its lower end to a rotary type shock absorber secured to the transom 21 of the railway truck frame 5 to dampen the pitching, rolling, nosing and swaying movements of the truck relative to the car body, primarily the pitching or galloping of the truck assembly around a horizontal transverse axis, an up and down motion of the truck assembly.
Pat. No. 2,352,039 discloses a rotary type shock absorber connected to the laterally extending end transom of the frame of a railway truck assembly at an intermediate location between the adjacent oppositely disposed wheels, the operating lever or crank of the rotary shock absorber being positioned for rotation on a longitudinally extending horizontal axis whereby its outer end moves up and down in an arcuate path, a connecting link connected between the outer end of the shock absorber crank and the bottom of a longitudinal sill extending down the midline under the railway car body, such shock absorber mounted in that position resisting the up and down motion which can be set up in a railway truck assembly sometimes known as "galloping," as well as providing resistance to other abnormal movements of the truck assembly relative to the railway car body.
Pat. No. 2,349,610 discloses an oscillating damper rigidly affixed to a railway car body, its operating lever extending downward for connection at its free end to a link rod connected to the railway truck assembly or bogie at the center of its laterally extending frame midway between the wheels on each opposite side, to dampen movements of the railway truck assembly relative to the railway car body.
Pat. No. 2,153,389 discloses a railway car sway control mechanism comprising brackets secured to the sills along opposite sides of the railway car at a location forward or rearward of the truck assembly and near the end of the railway car, a guideway comprising spaced apart upper and lower walls extending between the brackets to receive the outer free end portion of a tongue assembly extending from the railway truck, a pair of rotary shock absorbers mounted either on the tongue assembly or on the sills on opposite sides of the railway car, the operating levers of such shock absorbers connected to link rods which are secured to the car body when the shock absorbers are mounted on the tongue assembly and conversely to the tongue assembly when the shock absorbers are mounted on the sills of the car body, such mechanism damping or minimizing the lateral or side sway of railway cars.
In addition, the inventor is aware of reciprocating hydraulic cylinder type damping devices, comprising elongated cylinder and plunger assemblies, in which a first one is connected at one end to the laterally extending bolster of the railway truck assembly between a first side edge and the centrally positioned pivot bearing member with the opposite end of such elongated cylinder and plunger assembly being connected to the railway car at an underneath location spaced apart longitudinally from the truck bolster, and in which a second one of such elongated cylinder and plunger assemblies is connected at one end to the truck bolster at a location between the second opposite side edge thereof and its centrally positioned pivot bearing member, this second elongated cylinder and plunger assembly having its opposite end also connected to the railway car at an underneath location spaced apart longitudinally from the truck bolster.